The ingenuity of those who would violate a lock has led to the development of a wide variety of locking structures. Most of them are designed to provide security in a particular environment or circumstance. One of those circumstances is the locking of doors, and particularly exterior doors.
Several philosophies concerning the design of doorlocks currently prevail. One approach is to create a lock whose mechanism and size and apparent strength are hidden from view. The reasoning behind that approach is that the intruder will be discouraged because of his inability to assess what degree of difficulty will be involved in violating the lock.
An opposite approach is to employ a strong locking structure whose shape or other attributes make it difficult to apply force with which to violate the lock. The object of that philosophy is to make it apparent that violation will be a difficult task and, thus, to discourage any attempt to defeat the lock.